Parser Callbacks

The type of the "element started" callback. The first parameter is the
element name; the second are the (attribute, value) pairs. Return True to
continue parsing as normal, or False to terminate the parse.

The type of the "character data" callback. The parameter is the
character data processed. This callback may be called more than once while
processing a single conceptual block of text. Return True to continue
parsing as normal, or False to terminate the parse.